1. Field of the Invention
The present invention relates to an exchangeable type ink tank to be employed in an ink-jet printing apparatus and a production process therefor.
2. Description of the-Prior Art
As one example of the conventional exchangeable ink tank, an ink cartridge in a form illustrated in FIGS. 1 and 2 has been known in the art. FIG. 1 is an illustration showing a detail of the ink cartridge, and showing side elevation in section. FIG. 2 is a section showing a major part, such as an ink coupling portion of the ink cartridge or so forth.
As shown in FIGS. 1 and 2, an ink cartridge 10 includes an ink storage chamber 1 and a waste ink storage chamber 2. At the end of the ink storage chamber 1, rubber plugs 4 for piercing ink supply needle (not shown) at an ink-jet head side therethrough, are provided at two portions. Similarly, another rubber plug 4 is provided at the end portion of the waste ink storage chamber 2 at one portion. These rubber plugs 4 form a part of the ink coupling portion. Except for an ink communication portion 3 where the ink supply needle pierces, the rubber plug 4 is clamped by a housing 5 of the ink cartridge, an ink absorbing body 6 and a rubber plug retainer 7. With this construction, when the ink cartridge is removed from a printer, the ink stuck to the ink supply needle drawn from the cartridge associated with removable of the ink cartridge can be removed by the ink absorbing body 6. Thus, contamination of the inside of the printer by the ink stuck to the supply needle or plugging of the supply needle per se can be successfully prevented.
The waste ink storage chamber 2 is formed with two layer of storage portions mutually communicated at one ends. In the waste ink storage chamber 2, the portion where the ink supply needle pierces is located corresponding to the position corresponding to the lower layer storage portion. Namely, in the waste ink storage chamber 2, the supply needle connected to an ink supply passage of an ink-jet printing apparatus, passes through so that the waste ink discharged by the ejection recovery process and so forth may flow into the lower layer storage portion. Absorbing body 8 is filled in substantially whole waste ink storage chamber 2 so that the waste ink flowing into the lower layer storage portion can be absorbed by the absorbing body 8 in the lower layer storage portion. According to flow of the waste ink, region of the absorbing body 8 retaining the waste ink is gradually expanded to the absorbing body 8 in the upper layer storage portion. In conjunction therewith, a part of the waste ink exude from the absorbing body. On the other hand, a partitioning wall 2A is provided adjacent the end portion of the waste ink absorbing body 8 in the upper layer storage portion. By this, the ink exuding from the absorbing body 8 cannot flow into a portion right side of the partitioning wall 2A where the absorbing body is not filled until the amount of the waste ink exceeds a holding capacity of the absorbing body. Only when the accumulated waste ink amount flown into the waste ink storage chamber 2 exceeds the ink holding capacity of the absorbing body, the exuded ink overflows the partitioning wall 2A to move into the chamber at the right side and the level of the ink is gradually risen to contact with a waste ink detecting electrode d at a predetermined level. As a result, the waste ink storage chamber 2 filled with the waste ink can be detected to allow to urge exchanging of the ink cartridge. Also, at the upper side of the read end portion of the waste ink storage chamber 2, an atmosphere communicating portion 9 is provided. Via this communicating portion 9, the interior of the waste ink storage chamber 2 and the atmosphere outside of the ink cartridge are communicated.
However, since the ink storage chamber 1 and the waste ink storage chamber 2 are formed integrally in the conventional ink tank, the following problems to be solved are left mainly in viewpoint of production.
For example, the ink cartridge shown in Fig, 1 is required to weld a lid for integrally covering the ink storage chamber 1 and the waste ink storage chamber 2, namely the lid covering the entire surface of the cartridge as shown in FIG. 1, during production. In such production process, the following problems are encountered.
a) It is possible that debris of absorbing body constantly generated from the adjacent absorbing body 8 during production, may penetrate into the ink storage chamber 1, penetration of dart into which is not desirable. On the other hand, it is not easy to perform production with avoiding penetration of the debris of the absorbing body into the ink storage chamber 1 or to manage the dust. PA0 b) On the other hand, installation of the lid has to be performed by welding to seal respective chambers. However, as shown in FIG. 1, since the area to be welded is relatively large, a difficulty is frequently encountered to perform complete welding due to bowing of respective members. Particularly, it is relatively difficult to certainly weld the lid so as not to communicate the ink through the partitioning portion which separates the ink storage chamber 1 and the waste ink storage chamber 2. PA0 c) expensive device is required to require excessively high cost for small-lot production; PA0 d) when the size of the elastic body is slightly varied, new device becomes necessary for compression thereof; PA0 e) when the ink communication portion is extremely small, a space to insert the device for compressing the elastic body cannot be provided; PA0 f) the performance of the product can be fluctuated depending upon the condition of the quality of the device for compressing the elastic body; PA0 g) buckling of the elastic body relative to the internal wall of the housing can be caused; PA0 h) variation of the elastic body and new assembling device are required for forming optimal ink communicating portion with respect to a needle size; and PA0 i) for difficulty of assembling, assembling is performed before filling the ink and filling of the ink is performed thereafter by means of the needle, thus longer period is required since the diameter of the needle cannot be made to be sufficiently large, and excessively large needle may cause damage on the elastic body.
On the other hand, as shown in FIG. 2, the external diameter of the rubber plug 4 is formed to be greater than the internal diameter of the housing portion 5 in independent condition. The rubber plug 4 is thus assembled in the housing portion 5 along the direction of allow B with compressing in the diametrical direction (direction of arrow A in FIG. 2) by means of a predetermined device.
However, in the prior art, since the rubber plug 4 is assembled into the housing portion 5 with compressing in the diametrical direction, the following drawbacks are encountered.
Namely, since it is not easy to uniformly compress the elastic body, such as the rubber plug or so forth in the diametrical direction,